Preparation method of lithium iron phosphate battery suitable for being used in wide temperature range

A lithium iron phosphate battery, lithium iron phosphate technology, applied in battery electrodes, secondary batteries, battery pack components, etc., can solve the problems of low temperature performance, poor rate performance, poor low temperature performance, etc., and achieve cycle life and rate. Improved performance, excellent low temperature performance, and high consistency

Pending Publication Date: 2022-05-31
沈阳国科金能科技有限公司
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  • Application Information

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Problems solved by technology

[0005] In view of the current poor low-temperature performance of lithium iron phosphate, the purpose of the present invention is to provide a method for preparing a lithium iron phosphate battery suitable for use in a wide temperature range, by preparing a three-dimensional network structure composite carbon-coated battery with excellent low-temperature performance and rate performance Nano-scale lithium iron phosphate solves the problems of poor low-temperature performance and rate performance of lithium iron phosphate cathode materials used in lithium-ion batteries in the prior art

Method used

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  • Preparation method of lithium iron phosphate battery suitable for being used in wide temperature range
  • Preparation method of lithium iron phosphate battery suitable for being used in wide temperature range
  • Preparation method of lithium iron phosphate battery suitable for being used in wide temperature range

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Embodiment 1

[0044] In this embodiment, a preparation method of a lithium iron phosphate battery suitable for use in a wide temperature range is as follows:

[0045] (1) First weigh 9470g of nano-scale carbon-coated lithium iron phosphate, 250g of superconducting carbon black, and 200g of polyvinylidene fluoride and add them to a 20L mixing bucket in turn, and stir at a slow speed of 12rad / min for 2 hours to make the solid particles preliminarily mix evenly Then add carbon nanotube conductive liquid 1333.33g (in the carbon nanotube conductive liquid, carbon nanotube 5wt%, all the other are N-methylpyrrolidone), continue to add N-methylpyrrolidone, make the slurry solid content in the mixing tank reach 63wt%, when N-methylpyrrolidone is added, the stirring speed is 40rad / min and the dispersion speed is 3000rad / min, and the slurry is continuously finely kneaded for 3 hours by high shear force, so that each component is uniformly dispersed; and then divided into three times Add N-methylpyrrol...

Embodiment 2

[0053] In this embodiment, a preparation method of a lithium iron phosphate battery suitable for use in a wide temperature range is as follows:

[0054] (1) First weigh 9370g of nanoscale carbon-coated lithium iron phosphate, 200g of superconducting carbon black, and 2166.67g of carbon nanotube conductive liquid (in the carbon nanotube conductive liquid, carbon nanotube 5wt%, the rest is N-methylpyrrolidone ) and polyvinylidene fluoride 300g. Add 300 g of polyvinylidene fluoride and 5,000 g of N-methylpyrrolidone into a 20 L mixing tank, stir at a low speed of 10 rad / min for 2 hours to prepare glue, and vacuumize for later use. Then add carbon nanotube conductive liquid, superconducting carbon black, and lithium iron phosphate into the 20L mixing tank in sequence, and at the same time turn on the stirring speed of 45rad / min and the dispersion speed of 3500rad / min, and continuously refine the slurry through high shear force. Knead for 2 hours to disperse the components evenly;...

Embodiment 3

[0062] In this embodiment, a preparation method of a commercial lithium iron phosphate power battery:

[0063] (1) First take commercial power lithium iron phosphate 9370g, conductive carbon black 200g, polyvinylidene fluoride 300g, carbon nanotube conductive liquid 2166.67g (in the carbon nanotube conductive liquid, the carbon nanotube concentration is 5wt%, and the rest is N -methylpyrrolidone). Add 300 g of polyvinylidene fluoride and 5000 g of N-methylpyrrolidone into a 20 L mixing tank, stir at a low speed of 15 rad / min for 2 hours to prepare a glue solution, and vacuumize for later use. Then add carbon nanotube conductive liquid, conductive carbon black, and lithium iron phosphate in the order of the 20L mixing tank, and stir for 2 hours each time until the fineness is less than 26μm and the viscosity is 4000-6000N·m. Vacuum to -95kPa (gauge pressure), hold the pressure for 0.5 hours; filter the positive electrode slurry into the container through a 150-mesh stainless s...

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Abstract

The invention relates to the field of lithium ion battery manufacturing, in particular to a preparation method of a lithium iron phosphate battery which is suitable for being used in a wide temperature range of-40 DEG C to 55 DEG C and has excellent performance and stable reliability, and solves the problems of poor low-temperature performance and rate capability of a lithium iron phosphate positive electrode material for a lithium ion battery. On the basis of the traditional preparation process of the lithium iron phosphate battery, the electronic conductivity among active matter particles is improved by adjusting the types and proportions of a positive electrode, a negative electrode, a conductive agent and a binder in the battery, designing the optimal surface loading capacity, selecting a high-quality conductive agent type and forming a three-dimensional space conductive network on a positive electrode material layer and a negative electrode material layer; and the capacity of positive and negative active substances is exerted to the greatest extent. According to the present invention, the specially-blended low-temperature electrolyte is selected, and the concentration of the lithium salt in the electrolyte and the ratio of the main solvent additive are adjusted so as to provide good stability in the wide temperature zone, and the change of the ionic conductivity in the use temperature zone range is small so as to meet the use safety and the performance exertion of the battery at different temperatures;

Description

technical field [0001] The invention relates to the field of lithium ion battery manufacturing, in particular to a method for preparing a lithium iron phosphate battery suitable for use in a wide temperature range of -40°C to 55°C and having excellent performance, stability and reliability. Background technique [0002] Lithium iron phosphate (LiFePO4) was first proposed by Goodenough et al. in 1997 4 ) has been used as a positive electrode active material for lithium-ion batteries, LiFePO 4 With its advantages of high safety, long cycle life, low price and environmental friendliness, it is considered to be the most promising cathode active material for lithium-ion power batteries at present. Li-ion in LiFePO 4 Migration along one-dimensional channels in the crystal lattice greatly limits its diffusion rate, and one-dimensional channels are easily blocked by the appearance of impurity defects, further reducing its ionic conductivity. Compared with other cathode active mat...

Claims

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Application Information

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IPC IPC(8): H01M10/0583H01M10/0525H01M10/0567H01M10/0568H01M10/0569H01M4/136H01M4/1397H01M4/133H01M4/1393H01M50/434H01M50/449
CPCH01M10/0583H01M10/0525H01M10/0567H01M10/0568H01M10/0569H01M4/136H01M4/1397H01M4/133H01M4/1393H01M50/434H01M50/449Y02P70/50Y02E60/10
Inventor 杨林胡广剑徐晖曹贺闻雷吴敏杰
Owner 沈阳国科金能科技有限公司
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